Adulteration of food products, involving the replacement of high cost ingredients with lower grade and cheaper substitutes can be very attractive and lucrative for a food manufacturer or raw material supplier. The adulteration of food products is not only a major economic fraud, but can also have major health implications to consumers. In the 1980s, more than 400 deaths and 20,000 casualties occurred from the disease known as “Spanish toxic syndrome,” caused by the consumption of adulterated oil. Therefore, the detection of adulteration is of importance.
Olive oil production is a big business subject to serious attempts at fraudulent marketing of low-quality or adulterated oils. There are various methods for extracting the oil that yield different quality grades. Extra virgin olive oil is obtained from the olive Olea europaca sativa H by purely mechanical means, and the lower grade oils are obtained by solvent extraction, heat treatment, esterification, or refining. The composition of the oils is based on the fatty acids present in the tri-acyiglycerols and their location on the glycerol backbone. This composition varies not only with the type of oil and extraction method but also with geographical origin and meteorological effects during the growth and harvest of the olives. This variation can be used for oil authentication and the identification of adulteration. Various physical and chemical tests have been used to establish the authenticity of olive oil and to detect the level of adulterants in it. UV spectroscopy based on 208-210 and 310-320 nm has been widely used to detect the adulteration of virgin with the refined olive oil. A second derivative spectrometry method was reported to be able to detect the adulteration at a level of 6%.
Analysis of fatty acid profile after methylation using gas chromatography (GC) has been reported for the quantification of seed oils in olive oil. HPLC analysis of the fatty acid and triglycerides composition was also studied for detection of adulteration of olive oil. Nuclear magnetic resonance (NMR) analysis and a spectroflourometric methods have also been reported for detecting the adulteration of olive oil.
However, a drawback to some of these conventional methods of analyzing oils is that they are destructive and time-consuming, involving the hydrolysis and methylation of the resulting fatty acids. In addition, some of these approaches loose any information associated with the location of the fatty acids on the original glycerol backbone. Accordingly, authentication of the constituents of a food product is a major challenge in food product analysis.
Therefore, in light of the above discussion, it is apparent that what is needed is a method of measuring an amount of an organic substance contained within a food product that addresses one of more of the above discussed drawbacks.